In the art of vascular surgery, it is frequently desired to remove the inner layer from the vessel, which is fatty in nature, without cutting the vessel entirely through, but nevertheless cutting the inner layer to such a degree that, at a point some distance away, the blood vessel can be opened and the inner fatty sleeve pulled out of the vessel.
In an effort to solve this problem, there have been experiments in the design of an instrument which uses a guillotine type arrangement with an upper anvil member containing a dull blade resting on one side of the blood vessel and a hammerlike opposing jaw which held the blood vessel between the two members.
Experimental work has disclosed that an impact of sufficient magnitude with a dull blade to the outside of an unopened artery will fracture the intima without injury to the other layers of the artery (Arch. Surg. 1973, 107:664-668). Based upon this experimentation, a spring loaded instrument was made which activates two dull blades to deliver an impact of 4,000 gram centimeters to the outside of an artery. The dull blades were compressed against the vessel by a weak spring and impact to the dull blades was delivered by a separate, stronger spring which activates a hammer which struck a blow against the blades. This spring loaded instrument is clearly shown and described in U.S. Pat. No. 4,058,126. Although this instrument produced a linear fracture of the intima of the aorta, it was not applicable to all arteries as small arteries require a lesser impact than larger arteries. Thus, when the instrument of the '126 patent was used, a serious complication occurred in some small vessels as the blow inadvertently severed the small artery. This serious complication limited the usefulness of the instrument for vessels other than the aorta. It was thus necessary to design a new instrument which eliminates defects of past instruments and such an instrument is the subject of the present invention.